Effects of acid rain on growth and nutrient concentrations in Scots pine and Norway spruce seedlings grown in a nutrient-rich soil

The effects of artificially applied acid precipitation on growth and nutrient concentrations of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies [L.] Karst.) seedlings were investigated in a long-term acid irrigation experiment in field conditions. Seedlings of northern and southern origin were planted in boxes containing peat and composted soil rich in nutrients, and sprinkler irrigated with water acidified with nitric and sulphuric acids to pH 3 or pH 4 for periods varying from two to three and a half growing seasons during 1986-1989. Water irrigated (pH 5.4-7.6) and non-irrigated groups of seedlings were also included in the experiment. At the end of the experiment needles, main and lateral shoots and roots were collected from the seedlings for the determination of height growth and biomass partitioning, and for the analysis of S, N, Mg, P, K, Ca, Mn and Fe concentrations. The treatment effects compared to the irrigated control were studied using multivariate analyses of variance and covariance. In the pine seedlings the total dry matter production increased by 25-70% compared with the irrigated controls when the total wet deposition to the seedlings exceeded 67 kg S ha(-1) and 36 kg N ha(-1) (e.g. after two growing seasons' exposure of the pH 3 treatment). The increase was mainly due to an increase in needle dry weight (54-72% greater at pH 3) and root weight (20-65% greater at pH 3), whereas the height growth or shoot weight growth were less affected. The northern provenance pine seedlings responded more clearly to the pH 3 irrigation than the southern ones. The treatments had no consistent effects on any of the growth variables studied in the spruce seedlings, however. The pines had higher root and foliage Ca concentrations as a result of the acid irrigation, whereas in spruce, acid rain decreased the Ca concentration in needles and shoots. Root Mn and Fe concentrations were higher in both species as a result of the pH 3 treatment. A higher soil conductivity and Ca concentration resulted from the prolonged pH 3 treatment. The results strongly support the hypothesis that the long-term growth and nutrient allocation response of conifers to acid precipitation is dependent both on the tree species and on the nutritional status of the soil.     

Scots pine needle surfaces on radial transects across the north boreal area of Finnish Lapland and the Kola Peninsula of Russia

To gain an understanding of the characteristics of the needle surfaces of naturally regenerated Scots pine (Pinus sylvestris L.) and their geographical distribution, eight physicochemical variables were investigated within the north boreal forest area. The visibly undamaged needles were collected in autumn 1990 from 114 plots (3-5 pines per plot) along radial transects from the Monchegorsk and Nikel smelters, emitting SO2 and heavy metals, on the Kola Peninsula, Russia, to Finnish Lapland. The needles were examined by scanning electron microscopy (SEM) and measured for surface wettability using the droplet contact angle (DCA) method. Significant geographical south-north and west-east patterns could be observed in needle surface characteristics, correlating with emissions from the smelters and to climate. Despite the slightly higher initial DCAs (61.4-87.6 degrees) towards the north, the pine needle surfaces of the northernmost transects exhibited higher annual needle wettability change (ANWC) and wax erosion rate (AWER), expressed as the reduction in DCAs and epistomatal wax tube distribution (WTD) during one year, respectively, but a lower occurrence of particles and fungal hyphae than those of more southern transects. The higher ANWC was related to higher atmospheric SO2 concentration, and to the lower long-term temperature sum, but not clearly to annual precipitation. In the Monchegorsk smelter area, the current needles exhibited, on average, a 15% higher WTD and seven degree larger DCA, resulting in more hydrophobic needle surfaces than in Finnish Lapland, but during their first year, both the AWER and ANWC, were greatly increased. In Finnish Lapland, 30%, of all the epistomatal wax tubes disappeared from the needle surface during the first year, the value being 70% for the pines located 8 km from the smelter. The mineral composition of the particles deposited on the needle surfaces mirrored that of the minerals being produced by the smelters (e.g. FexSx, CuFeS2, NixSx, FexOx). Stomatal densities were in the range of 71.1-141.7 stomata mm(-2). The lower densities of stomata on needles close to the smelters correlated with reduced number of needle age classes of the pines, higher dry weights, higher pollutant accumulation and lower Mn and Zn concentrations in the needles. The AWER and ANWC were able to indicate the most seriously deteriorated needle surfaces on a regional scale, e.g. including the surroundings of both smelters, although the plot-specific relationships between 'needle surface variables' and 'pollution variables' were generally weak. The present study showed that the exposure of pine needles to the combined effects of ambient pollutants and harsh climate led to a deterioration in the physicochemical characteristics of the epicuticular wax, which may have serious ecophysiological consequences in the long term.     

Effect of the temperature and the exclusion of UVB radiation on the phenolics and iridoids in Menyanthes trifoliata L. leaves in the subarctic

The long-term effects of UVB exclusion and temperature on the methanol extractable (ME) phenolics (flavonoids, phenolic acids) and iridoids of Menyanthes trifoliata L. (Mt) leaves were studied in northern Finland (68°N) using wooden frames covered with filters for UVB exclusion (polyester filter), control (cellulose acetate filter) and ambient (no filter) conditions. Analysis of ambient plots showed no effect of the daily mean temperature (2σ = 1.58 °C) on the leaf ME compound content and composition, but minimum temperatures decreased the flavonol content. UVB exclusion did not affect the total ME compound content but significantly decreased the proportion of flavonols concomitantly with an increase in iridoids. Due to its high iridoid content, Mt appears as an interesting model plant for studying the iridoid biosynthesis and its regulation under stress conditions.     

Conservation and Management for Multiple Species: Integrating Field Research and Modeling into Management Decisions

Multiple-species reserves aim at supporting viable populations of selected species. Population viability analysis (PVA) is a group of methods for predicting such measures as extinction risk based on species-specific data. These methods include models that simulate the dynamics of a population or a metapopulation. A PVA model for the California gnatcatcher in Orange County was developed with landscape (GIS) data on the habitat characteristics and requirements and demographic data on population dynamics of the species. The potential applications of this model include sensitivity analysis that provides guidance for planning fieldwork, designing reserves, evaluating management options, and assessing human impact. The method can be extended to multiple species by combining habitat suitability maps for selected species with weights based on the threat faced by each species, and the contribution of habitat patches to the persistence of each species. These applications and extensions, together with the ability of the model to combine habitat and demographic data, make PVA a powerful tool for the design, conservation, and management of multiple species reserves.     

UV-absorbing compounds in subarctic herbarium bryophytes

The UV-B-absorbing compounds of herbarium specimens of 10 subarctic bryophyte species collected during the years 1926-1996 and available at the Botanical Museum, University of Oulu, were studied. We studied whether herbarium specimens reflect changes in the past radiation climate through their methanol-extractable compounds. The order of gametophytes based on the average amount of total compounds (sum of A280-320 nm) per mass from the lowest to the highest was Polytrichum commune, Pleurozium schreberi, Hylocomium splendens, Sphagnum angustifolium, Dicranum scoparium, Funaria hygrometrica, Sphagnum fuscum, Sphagnum warnstorfii, Sphagnum capillifolium and Polytrichastrum alpinum, and the amount of UV-B-absorbing compounds per specific surface area correlated with the summertime daily global radiation and latitude. P. alpinum, F. hygrometrica and three Sphagnum species seem to be good indicators for further studies. The amount of UV-B-absorbing compounds revealed no significant trends from the 1920s till the 1990s, with the exception of S. capillifolium, which showed a significant decreasing trend.     

Heterogeneity of nodularin bioaccumulation in northern Baltic Sea flounders in 2002

The cyanobacterial hepatotoxin nodularin is abundantly produced by the cyanobacterium Nodularia spumigena in the Baltic Sea during July-August. Nodularin is a potent hepatotoxin and a tumour promoter, distributed in various Baltic Sea environmental compartments, especially food webs involving mussels. Flounders receive nodularin through consumption of blue mussels. In this study nodularin concentrations in individual flounders (liver) were examined between July and September 2002 (six sample sets, four to 10 samples/set), providing information about contribution of sampling on estimates of bioaccumulation intensity. Toxin was determined using liquid chromatography/mass spectrometry (LC/MS) and enzyme-linked immunosorbent assay (ELISA). Additionally, liver histopathology was examined. Observed toxin concentrations were ND-390 microg kg(-1) dw (LC/MS) and 20-2230 microg kg(-1) dw (ELISA), with maximum concentrations in September (ELISA). The ELISA protocol generally resulted in higher, up to approximately 10-fold, toxin concentrations than LC/MS, with increasing difference toward September. This difference may have originated from different extraction solvents in LC/MS and ELISA, ion suppression in LC/MS, and temporal increase in nodularin metabolites detectable with ELISA. The differences in toxin concentrations between individual liver samples were considerable with relative standard deviation values of 20-154% (LC/MS) and 28-106% (ELISA). Since the precision of the ELISA method employed was <25% and that of LC/MS <10%, it can be concluded that the largest source of error in bioaccumulation estimates may be an inadequate number of samples. Although there were tissue lesions in several liver samples, occurrence of lesions was not related to toxin concentrations.     

Detecting Extinction Risk from Climate Change by IUCN Red List Criteria

Anthropogenic climate change is a key threat to global biodiversity. To inform strategic actions aimed at conserving biodiversity as climate changes, conservation planners need early warning of the risks faced by different species. The IUCN Red List criteria for threatened species are widely acknowledged as useful risk assessment tools for informing conservation under constraints imposed by limited data. However, doubts have been expressed about the ability of the criteria to detect risks imposed by potentially slow‐acting threats such as climate change, particularly because criteria addressing rates of population decline are assessed over time scales as short as 10 years. We used spatially explicit stochastic population models and dynamic species distribution models projected to future climates to determine how long before extinction a species would become eligible for listing as threatened based on the IUCN Red List criteria. We focused on a short‐lived frog species (Assa darlingtoni) chosen specifically to represent potential weaknesses in the criteria to allow detailed consideration of the analytical issues and to develop an approach for wider application. The criteria were more sensitive to climate change than previously anticipated; lead times between initial listing in a threatened category and predicted extinction varied from 40 to 80 years, depending on data availability. We attributed this sensitivity primarily to the ensemble properties of the criteria that assess contrasting symptoms of extinction risk. Nevertheless, we recommend the robustness of the criteria warrants further investigation across species with contrasting life histories and patterns of decline. The adequacy of these lead times for early warning depends on practicalities of environmental policy and management, bureaucratic or political inertia, and the anticipated species response times to management actions. Detección del Riesgo de Extinción a partir del Cambio Climático por medio del Criterio de la Lista Roja de la UICNKeith et al.     

Influence of solar UV radiation on the nitrogen metabolism in needles of Scots pine (Pinus sylvestris L.)

Needles of 20-year-old Scots pine (Pinus sylvestris L.) saplings were studied in an ultraviolet (UV) exclusion field experiment (from 2000 to 2002) in northern Finland (67 °N). The chambers held filters that excluded both UV-B and UV-A, excluded UV-B only, transmitted all UV (control), or lacked filters (ambient). UV-B/UV-A exclusion decreased nitrate reductase (NR) activity of 1-year-old needles of Scots pines compared to the controls. The proportion of free amino acids varied in the range 1.08-1.94% of total proteins, and was significantly higher in needles of saplings grown under UV-B/UV-A exclusion compared to the controls or UV-B exclusion. NR activity correlated with air temperature, indicating a “chamber effect”. The study showed that both UV irradiance and increasing temperature are significant modulators of nitrogen (N) metabolism in Scots pine needles.     

Fire Management,Managed Relocation,and Land Conservation Options for Long‐Lived Obligate Seeding Plants under Global Changes in Climate,Urbanization, and Fire Regime

Most species face multiple anthropogenic disruptions. Few studies have quantified the cumulative influence of multiple threats on species of conservation concern, and far fewer have quantified the potential relative value of multiple conservation interventions in light of these threats. We linked spatial distribution and population viability models to explore conservation interventions under projected climate change, urbanization, and changes in fire regime on a long‐lived obligate seeding plant species sensitive to high fire frequencies, a dominant plant functional type in many fire‐prone ecosystems, including the biodiversity hotspots of Mediterranean‐type ecosystems. First, we investigated the relative risk of population decline for plant populations in landscapes with and without land protection under an existing habitat conservation plan. Second, we modeled the effectiveness of relocating both seedlings and seeds from a large patch with predicted declines in habitat area to 2 unoccupied recipient patches with increasing habitat area under 2 projected climate change scenarios. Finally, we modeled 8 fire return intervals (FRIs) approximating the outcomes of different management strategies that effectively control fire frequency. Invariably, long‐lived obligate seeding populations remained viable only when FRIs were maintained at or above a minimum level. Land conservation and seedling relocation efforts lessened the impact of climate change and land‐use change on obligate seeding populations to differing degrees depending on the climate change scenario, but neither of these efforts was as generally effective as frequent translocation of seeds. While none of the modeled strategies fully compensated for the effects of land‐use and climate change, an integrative approach managing multiple threats may diminish population declines for species in complex landscapes. Conservation plans designed to mitigate the impacts of a single threat are likely to fail if additional threats are ignored. Manejo de Incendios, Reubicación Administrada y Opciones de Conservación de Suelo para Plantas de Vida Larga con Sembrado Obligado bajo los Cambios Globales en el Clima, la Urbanización y el Régimen de Incendios     

The effects of UV exclusion on the soluble phenolics of young Scots pine seedlings in the subarctic

The characteristics of UV-absorbing compounds, particularly soluble phenolics, were studied in needles of 63-day-old seed-grown Scots pine (Pinus sylvestris L.) seedlings of two provenances in a UV exclusion field experiment at Pallas-Ounastunturi National Park in Finnish Lapland (68 degrees N, 270 m a.s.l.). The experiment used the following plastic filters in exclosure treatments to manipulate the spectral balance of natural irradiance: (1) 'control' (a polyethene plastic filter); (2) 'UV-B exclusion' (a clear polyester filter); and (3) 'UV-B/UV-A exclusion' (a clear acryl plate). Polyethene transmitted 89% of the ambient levels of total UV (280-400 nm), polyester transmitted 75% of the total UV, but only 0.6% of the UV-B (280-315 nm) component, while acryl plate transmitted 0.2% of UV (280-360 nm). The research also included (4) 'Ambient' plants that were not subjected to any treatment exclosures. After the 58 day UV exclusion, significant (p<0.0001) differences due to treatments were determined for a kaempferol derivative, kaempferol 3-glucoside, and a quercetin derivative, the quantities of which ranged from 0.23 to 0.45, 0.42 to 1.34 and 0.39 to 0.75 micromol g FW(-1), respectively, depending on treatment and provenance. Overall, Scots pine seedlings grown at ambient UV radiation (PAS300, Caldwell's generalized Plant Action Spectrum (PAS) normalized at 300 nm, 72 mW m(-2)) or under a control had significantly (p<0.05) higher quantities of soluble phenolics than seedlings grown under UV-B or UV-B/UV-A exclusion treatments. There were no significant differences in the quantity of soluble phenolics between the two exclosure treatments or between the two Scots pine provenances. The sums of diacylated flavonol glucosides ranging from 3.75 to 4.55 micromol g FW(-1) depending on treatment and provenance, were already present at very low UV-levels under the UV-B/UV-A exclusion treatment. The present study indicated that soluble phenolics, particularly the diacylated flavonol glucosides, may provide an effective preformed protection for young Scots pine seedlings against UV-B and UV-A radiation.